JPH01166838A - Manufacture of flat both face needle - Google Patents

Abstract

PURPOSE:To improve a production efficiency by pressing the wire of the cross section area considering the elongation at pressing time, forming a flat both face handle part as well and regulating the width dimension between the side faces orthogonal with a flat face. CONSTITUTION:A wire sectional area is calculated in advance by considering the wire elongation at pressing time. On the die 7 for press forming the chamfer part having the flat part 8 forming a forming flat face 6 and the recessed face 9 curved in circular arcuated shape and rounding both sides of the recessed face is formed. A pair of the flat faces 6 are formed on the handle part 5 by press-forming the wire and maintaining the dimension (l) between both side faces 51, 51 in the specified dimension to obtain a product needle. Deburring, edge beveling, cutting and grinding works are omitted because the side face 51 is subjected to bulged forming with being regulated at its width dimension (l). Consequently the production efficiency of a product is improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a method for manufacturing sewing machine needles from wire using a forming press, and the present invention is a double-sided flat sewing machine needle in which two flat surfaces are press-formed on the handle of the needle. The present invention relates to a manufacturing method.

[Conventional technology]

Conventional press-molded sewing machine needles, for example,
As proposed in Japanese Patent No. 168740, a needle stem with a substantially reduced cross-sectional dimension is formed from the needle handle to the needle tip, and a flat surface is formed on the handle and a flat surface is formed on the needle stem by pressing or rolling. The thread groove is pressed, and the selvedge protruding from the press mold is polished with a grinder or cut off with a milling cutter to produce a product.

[Problem that the invention seeks to solve]

In this conventional method, the wire portion is pressed flat in the range of the needle stem and handle to be formed, and the needle groove is pressed and the hole is simultaneously pressed to flatten the needle stem to almost the cross-sectional thickness. Grinding or milling to remove the remaining flattened edges with a cutting tool results in high costs, does not increase productivity, and does not improve dimensional accuracy. With needles, two needles are used against a flat surface, so if there is variation in dimensional accuracy, the needle becomes unusable, and finishing and quality control during manufacturing are also complicated.

The present invention accurately eliminates the drawbacks of manufacturing sewing machine needles by forming them using conventional presses, makes it possible to reduce the number of processing steps, and manufactures double-sided flat needles with high dimensional accuracy and good quality with high productivity. The purpose is to provide a method that can be used.

[Means for solving problems]

The present invention is a manufacturing method in which a flat sewing machine needle is produced by pressing a wire serving as a needle bar material into a needle stem and a handle using a press mold, and the method is calculated in advance in consideration of the wire elongation during pressing. A pair of opposing flat surfaces are formed on the handle by pressing a wire having a cross-sectional area of This is a method for manufacturing a double-sided flat sewing machine needle characterized by press working.

[For production]

In the manufacturing method of the present invention, when producing a sewing machine needle in which a thread groove and a needle hole are formed in a needle stem with a needle tip at one end and a handle at the other end, the wire diameter is calculated in advance in consideration of the elongation during pressing. Using a wire with a certain circular or square cross section, a pair of opposing flat surfaces are formed on the handle using a press molding die to form a double-sided flat handle, and the width dimension between both sides in the direction perpendicular to the flat surfaces is By pressing the sides to prevent overlapping, it is possible to efficiently produce double-sided flat sewing machine needles with high dimensional accuracy.

〔Example〕

An embodiment of the present invention will be described with reference to FIGS. 1 to 6. A needle stem 4 has a needle tip l at one end and a thread groove 3 with a needle hole 2.
When making a sewing machine needle in which a handle 5 is formed through a tapered portion 4I, the needle stem 4 and the handle 5 are formed by pressure forming using a press molding die 7 from a wire serving as a material for the needle bar. Press a wire with a cross-sectional area calculated in advance by taking into account the elongation of the wire during pressing, and press the opposite flat surface 6.6 into the handle 5.
A pair of flat surfaces 6 are formed on both sides to form a double-sided flat handle portion.
Both sides in the direction perpendicular to 5. ．． 5. A double-sided flat sewing machine needle is produced by press working while maintaining a predetermined width dimension l.

In this case, in the pressing step, the side surfaces 51° 51 facing each other in the pressing direction or in a direction perpendicular thereto are pressed into curved surfaces with no edges and a circular cross section. After the wire is rolled into a rectangular cross-section, it is preferable to process the wire into the mountain-shaped curved surface with a circular arc whose radius is the distance from the opposing short sides to the center point.

Note that the double-sided flat handle can be processed before or after the forming process of the needle stem 4, but the needle stem material may be rolled or press-formed using a band-shaped wire or linear wire with a rectangular cross section. However, a mold with a predetermined cross-sectional area is selected in advance in consideration of the elongation of the material during pressing, and in particular, the press molding die 7 has a flat surface 8 forming the flat surface 6 of the press molding die 7.
Both sides of the needle stem 4 are cut using a die having a concave surface 9 curved in an arc shape and having rounded chamfers on both sides of the concave surface. ．． 5. It is preferable to press so that a mountain-shaped curved surface is formed at the same time on the short side surface, and if necessary, a split mold in which only the flat surface 8 slides can be selected and used. In any case, it is pressed from both sides so that the width l does not exceed, and has a shape with no edges and good surface support.

The side surfaces 5+, 5+ of the curved surface are formed by forming the mountain-shaped curved surface with a circular arc whose radius is the distance from the center point P of the needle stem 4 to the side surface 51, and by chamfering. It is designed to avoid forming edges during processing, and the needle stem material has a rectangular cross section with room for expansion during pressing, and both opposing long side surfaces are flat surfaces 6, and the thickness direction 5. Press on the sides. It may also be in a press form in which the needle is bulged out to form a sewing machine needle.

In addition, when using equipment with a needle stem material having a rectangular cross section, it becomes possible to perform press processing using the press molding die 7.7 by selecting a predetermined cross-sectional area that can be used as is, and perform the necessary preliminary processing. What is required is to appropriately process the metal distribution of the needle stem material to facilitate commercialization.

In the figure, 10.11 is a mold holding part.

It should be noted that the press molding molds 7 may be used in pairs, and a combination of a movable side mold and a fixed side mold may be used, or both sides may be pressed under clamping pressure with a movable side mold, and both side surfaces may be shaped at the same time. It may be selected arbitrarily depending on the relationship with the mold 7 or the needle stem material to form the upper and lower surfaces by pressing on the side surface 5I, or by using a continuous wire rod.
It is better to process it automatically.

In the example shown in FIG. 7, the side surface 5 of the curved surface of the handle 5 extends in the pressing direction of the press molding die 7. was formed.

〔Effect of the invention〕

The present invention forms a double-sided flat handle by pressing a wire with a cross-sectional area calculated in advance in consideration of the wire elongation during pressing to form a pair of opposing flat surfaces on the handle. Double-sided flattened needles can be obtained by press working while maintaining the medium dimension between the two sides in orthogonal directions, and productivity can be significantly improved by omitting the need for deburring and edge chamfering. At the same time, the dimensional accuracy has been improved, and it is easy to make the side surface of the handle of the sewing machine needle round, and the surface roughness has been significantly improved, so it can be used effectively as a product as it is without the need for surface finishing. The inconveniences and drawbacks of processing can be eliminated, and the processing process can be simplified.
Production efficiency can be greatly improved, and the grinding and polishing work that is an impediment to mass production can be omitted, the outer peripheral surface can be made smoother, the surface grip can be improved, the sewing properties have been significantly improved, the product value has increased, and the production cost has been increased. It also has the effect of significantly reducing costs.

[Brief explanation of the drawing]

The drawings show an embodiment of the method of the present invention, in which Fig. 1 is a perspective view of the product, Fig. 2 is a vertical cross-sectional view of a press molding die, Fig. 3 is a side view thereof, and Fig. 4 is a view during press operation. Vertical cross-sectional view of the mold, No. 5
6 is an enlarged sectional view taken along line 11 in FIG. 1, and FIG. 7 is a longitudinal sectional view of another embodiment of the mold. 1...needle tip, 2...needle hole, 3...thread groove, 4...
Needle stem, 4... Taper part, 5... Handle part, 5.・・・
・Side surface, 6...Flat surface, 7...Mold for press molding,
8...Flat surface, 9...Concave surface. Patent applicant Organ Needle Co., Ltd.

Claims (3)

[Claims] (1) In the manufacturing method in which wire, which is the needle material, is pressed into a needle stem and handle using a press mold to form a flat sewing machine needle, the wire used as the needle material is pre-calculated in consideration of the wire elongation during pressing. A pair of opposing flat surfaces are formed on the handle by pressing a wire having a cross-sectional area of A method for manufacturing a double-sided flat sewing machine needle. (2) In the pressing step, side surfaces facing each other in the pressing direction or in a direction orthogonal thereto are press-formed into mountain-shaped curved surfaces without edges. Production method. (3) The pressing step is to roll a wire with a circular cross section into a rectangular cross section, and then process the wire into the mountain-shaped curved surface with a circular arc whose radius is the distance from the opposite short side to the center point. A manufacturing method according to claim 1 or 2.